Compound A is a known compound described in Japanese patent publication (Unexamined) Nos. 225,182/84, 172,996/85, and U.S. Pat. No. 4,564,609 as a compound having improving activities for consciousness disturbance and memory disorder.
Each example 1 of the aforesaid patent publications describes that Compound A was crystallized by triturating with a small amount of methanol and the resulting crystals contained 1/2 mol of water on the basis of the elemental analysis.